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Ask Chris (aka- Moose) Your Own Question
Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 44534
Experience:  16 years experience
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My 2004 F150 keeps giving a false overheating. The gauge

Customer Question

My 2004 F150 keeps giving a false overheating. The gauge will quickly peg out to hot but the engine is not hot at all. Once I turn the key off it will reset and be fine for a while. I have read many forums where other have experienced this problem but it seems none have resolved it. I have changed coils and temp sensors, all to no avail. Several mechanics that I have consulted are also unsure of the cause. Any sugg
JA: Is the car in "Park" or "Neutral?" Do you know if your car has a "wheel lock" feature?
Customer: While I'm driving
JA: Are you fixing your F150 yourself? What have you tried so far?
Customer: Had at shop for 3 weeks. Replaced temp sensors and oil temp sensor.
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 1 month ago.
Category: Ford
Expert:  Chris (aka- Moose) replied 1 month ago.

Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner past midnight.

Have you monitored the temp reading the PCM is getting when this occurs using a scan tool?

What liter engine?

How often is this occurring?

Customer: replied 1 month ago.
It's was in the shop for 3 weeks for this issue so They did that. Every thing was normal. The gauge would be fine then peg hot when the engine was not. While driving if I put in neautral and slam on gas for a fee seconds after it pegged hot the gauge would read normal. Or put in neutral cut off then back on it would go back to normal. 5.4 v8 just installed 2 months ago. Problem started directly after installation. No info prior to installation didn't run when purchased.
Customer: replied 1 month ago.
Occurs every time I drive, at different times during the trip.
Expert:  Chris (aka- Moose) replied 1 month ago.

It appears that everyone has done all the checks and ruled this out to be electrically related.

I suggest you do steps that include replacing the thermostat, inspecting the water pump impeller, confirm no restriction in the radiator, and do a cooling system pressure test to see if there are air pockets in the cooling system preventing coolant flow. Reving the engine will not effect the coolant temp reading electrically but it will change the speed of the water pump which makes this look to be more related to a coolant flow concern.

This is my 1st answer of what can be many. You the website and myself expect you to have a ~~~5 STAR EXCELLENT~~~ experience with my help. At the top of your screen is the rating box that you only get to use once. Please make sure to complete the mandatory rating when ready or reply and say "I am pleased with my answer". Not rating or rating 1-2 stars does not benefit you nor me in any way.

Thanks Moose.

Customer: replied 1 month ago.
Should they have replaced water pump with new engine install or is that a separate thing?
Expert:  Chris (aka- Moose) replied 1 month ago.

I always do but I can not speak for what others do.

Customer: replied 1 month ago.
Just thinking out loud here. When the gauge does spike to hot, I put the truck in neutral cut off the engine and then cut it back on instead of rev the engine. The gauge instantly goes back to normal. There never is a true over heat. Sometimes I rev it and it goes back sometimes I cut it off and right back on it goes right back. Could it still be a cooling issue if just cutting it off then right back on fixes the problem as well?
Expert:  Chris (aka- Moose) replied 1 month ago.

Yes this still can be a momentary overheat that that the sudden rise in rpm on the pump or the loss of pump pressure from shutting it off is resolving.